Sulfonic acids of aromatic aminothiazoles.



rm rap slur JOHANN HUISMANN, F COLOGNE, GERMANY, ASSIGNOR TO SYNTHETIC PATENTS CO. INC., OF NEW YORK, N. Y., A CORPORATION OF NEW YORK.

SULFONIC ACIDS OF AROMATIC AMINOTHIAZOLES.

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- They are obtained by the baking process for instance by heating the dehydrothiotoluidm, its homologues and substitution products as well as the corresponding prunulins or the known monosulfonic acids of all these compounds with sulfuric acld to high temperatures, suitably in oacuo. The new bodies are characterized by containing H1 their molecule the aggregation:

s R/ c u soan NHz (R meaning an aryl group and the sulfonic group being 1n ortho position to the ammo ,group.) These sulfonic acids are generally yellowish crystalline compounds soluble in the shape of their alkaline salts with a bluish fluorescence in water, difiicultly soluble in alcohol, ether, ligroin, benzene and forming yellowish colored diazo compounds.

In order to illustrate the new process more fully the following example is given, the parts being by weight z-320parts of the dehydrothiotoluidin sulfonic acid of the formula s\ c-- -um CH, soni I are intimately mixed with a solution of 196 parts of monohydrated sulfuric acid in water and then evaporated to dryness. paste thus obtained is heated for several hours in oacuo in a vessel provided with a stirrer and a reflux condenser to temperaturesof from 275-290 C. in an oil bath. When Water does not distil-any more the Specification of Letters Patent.

The

Patented Aug. 10, 1915.

Application filed June 2, 1914. Serial No. 842,459.

process is complete. The product is dissolved in hot water and the sulfuric aciddn excess is precipitated from the solution by the addition of milk of lime. From the solution filtered off from the sulfate of lime the calcium oxid is precipitated by means of sodaand the solution is then evaporated to dryness. Thus the sodium salt of a new dehydrothiotoluidin disulfonic acid is obtained in the shape of uncolo: ad leaflets which are easily soluble in water with a pure blue fluorescence. The free dehydrothiotoluidin disulfonic acid is obtained from the sodium salt by the addition of dilute acid in tne shape of crystalline yellow leaflets, soluble in water witha yellow coloration. This acid forms a yellow colored diazo compound, easily soluble in water.

The same disulfonic acid can be obtained by sulfonating with fuming sulfuric acid the dehydrothiotoluidin-mono-sulfonic acid obtained by means of the baking process from the dehydrothiotoluidin itself.

The new disulfonic acid has most probably the following formula:

(R meaning an aryl group and the sulfonic' group being in ortho position to the amino group) which are yellowlsh crystalline products soluble in the shape of their alkaline salts in water with a bluish fluorcscen'ce, difiicultly soluble in alcohol, ether, benzene, ligroin; forming yellowish colored diazo compounds; and being valuable intermediate products for the preparation of dyestuffs, substantially as described. 4

2. The herein described ortho-sulfonic acids of aromatic aminothiazole compounds containing in. their molecule the aggregation:

which are yellowish crystalline pro ucts soluble in the shape of their alkaline'salts in water with a bluish fluorescence, diflicultly soluble in alcohol, ether, benzene, ligroin; forming yellowish colored diazo compounds; and being valuable intermediate products for the preparation of dyestuffs, substantially as described.

3. The herein described ortho-sulfonic acids of aromatic aminothiazole compounds aryl containing in their molecule the aggregation /so3u which are yellowish. crystalline products soluble in the shape oi'gtheir alkaline salts in water with a bluish fluorescence, diilicultly soluble in alcohol, ether, benzene, ligroin; forming yellowish colored diazo' compounds; and being valuable intermediate products for the preparation of dyestufl's, substantially as described.

' ahThe herein described ortho-sulfonic acids of aromatic aminothiazole compounds containing in their molecule the aggregation:

which are yellowish crystalline products soluble in the shape of their alkaline salts in water with a. bluish fluorescence, difiicultly nng soluble in alcohol, ether, benzene, ligroin;

forming yellowish colored diazo compounds; and being Valuable inte mediate products for the preparation of dyestuffs,

substantially as described.

The herein described dehydrothiotoluidin disulfonic acid having most probably the formula: 

